Organic light emitting device and display device including the same

ABSTRACT

An organic light emitting device and a display device, the organic light emitting device including a first electrode; a hole transport region on the first electrode; an emission layer on the hole transport region; an electron transport region on the emission layer; and a second electrode on the electron transport region, wherein the hole transport region includes a compound represented by the following Formula 1:

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2014-0152961, filed on Nov. 5, 2014, inthe Korean Intellectual Property Office, and entitled: “Organic LightEmitting Device and Display Device Including The Same,” is incorporatedby reference herein in its entirety.

BACKGROUND

1. Field

Embodiments relate to an organic light emitting device and a displaydevice including the same.

2. Description of the Related Art

Flat display devices are mainly classified as a light emitting type anda light receiving type. The light emitting type may include a flatcathode ray tube, a plasma display panel, an organic light emittingdisplay (OLED), etc. The OLED is a self-luminescent display and hasadvantages of wide viewing angles, good contrast, and rapid responsetime.

Thus, the OLED may be applicable in a display for a mobile device suchas a digital camera, a video camera, a camcorder, a personal digitalassistant, a smart phone, an ultra-thin laptop, a tablet personalcomputer, a flexible display, etc., or a large-sized electronic productssuch as an ultra-thin television or a large-sized electric products, andreceives much attention.

The OLED may embody color based on the principle that holes andelectrons injected from a first electrode and a second electrode arerecombined in an emission layer, and excitons obtained by thecombination of the injected holes and electrons emit light during thetransition thereof from an excited state to a ground state.

SUMMARY

Embodiments are directed to an organic light emitting device and adisplay device including the same

Embodiments provide organic light emitting devices including a firstelectrode, a hole transport region provided on the first electrode, anemission layer provided on the hole transport region, an electrontransport region provided on the emission layer, and a second electrodeprovided on the electron transport region. The hole transport regionincludes a compound represented by the following Formula 1.

In the above Formula 1, X, Y and Z are independently selected from thegroup consisting of hydrogen, deuterium, a substituted or unsubstitutedaromatic ring having 5 to 30 carbon atoms, a substituted orunsubstituted condensed aromatic ring having 5 to 30 carbon atoms, asubstituted or unsubstituted heteroaromatic ring having 5 to 30 carbonatoms, a substituted or unsubstituted condensed heteroaromatic ringhaving 5 to 30 carbon atoms, a substituted or unsubstitutedheteroaromatic ring having 5 to 30 carbon atoms and including N, S or O,and a substituted or unsubstituted condensed heteroaromatic ring having5 to 30 carbon atoms and including N, S or O.

In some embodiments, X, Y and Z may be independently selected from thegroup consisting of hydrogen, deuterium, a substituted or unsubstitutedaryl group having 5 to 30 carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 carbon atoms, a substituted orunsubstituted aryloxy group having 5 to 30 carbon atoms, a substitutedor unsubstituted arylamino group having 5 to 30 carbon atoms, asubstituted or unsubstituted diarylamino group having 5 to 30 carbonatoms, and a substituted or unsubstituted arylakyl group having 5 to 30carbon atoms.

In other embodiments, X, Y and Z may be independently selected from thegroup consisting of a phenyl group, a naphthyl group, a biphenyl group,a terphenyl group, an anthracene group, a fluorenyl group and acarbazolyl group.

In still other embodiments, the hole transport region may include atleast one compound selected from compounds represented in the followingFormula 2.

In even other embodiments, the emission layer may include a compoundrepresented by the following Formula 3.

In the above Formula 3, Ar¹¹ and Ar¹² are independently selected fromthe group consisting of hydrogen, deuterium, a substituted orunsubstituted aromatic ring having 5 to 30 carbon atoms, a substitutedor unsubstituted condensed aromatic ring having 5 to 30 carbon atoms, asubstituted or unsubstituted heteroaromatic ring having 5 to 30 carbonatoms, a substituted or unsubstituted condensed heteroaromatic ringhaving 5 to 30 carbon atoms, a substituted or unsubstitutedheteroaromatic ring having 5 to 30 carbon atoms and including N, S or O,and a substituted or unsubstituted condensed heteroaromatic ring having5 to 30 carbon atoms and including N, S or O, and m and n areindependently an integer of 0 to 3.

In yet other embodiments, Ar¹¹ may be a substituted or unsubstitutedarylene group having 7 to 30 carbon atoms or a substituted orunsubstituted heteroarylene group having 7 to 30 carbon atoms, where inthe case that m is 0, Ar¹¹ is a single bond. Ar¹² may be a substitutedor unsubstituted aryl group having 5 to 30 carbon atoms or a substitutedor unsubstituted heteroaryl group having 5 to 30 carbon atoms, where inthe case that m or n is an integer greater than or equal to 2, Ar¹¹ maybe the same or different, Ar¹² may be the same or different, and Ar¹¹and Ar¹² may be the same or different from each other.

In further embodiments, Ar¹¹ may be a substituted or unsubstitutedphenyl group or a substituted or unsubstituted naphthyl group.

In still further embodiments, the emission layer may include at leastone compound selected from compounds represented in the followingFormula 4.

In even further embodiments, the electron transport region may includeat least one compound selected from compounds represented in thefollowing Formula 5.

In the above Formula 5, Ar¹, Ar², Ar³ and Ar⁴ are independently selectedfrom the group consisting of hydrogen, deuterium, a substituted orunsubstituted aromatic ring having 5 to 30 carbon atoms, a substitutedor unsubstituted condensed aromatic ring having 5 to 30 carbon atoms, asubstituted or unsubstituted heteroaromatic ring having 5 to 30 carbonatoms, a substituted or unsubstituted condensed heteroaromatic ringhaving 5 to 30 carbon atoms, a substituted or unsubstitutedheteroaromatic ring having 5 to 30 carbon atoms and including N, S or O,and a substituted or unsubstituted condensed heteroaromatic ring having5 to 30 carbon atoms and including N, S or O, and o, p, q and r areindependently an integer of 1 to 3.

In yet further embodiments, Ar¹, Ar², Ar³ and Ar⁴ may be independently asubstituted or unsubstituted aryl group having 5 to 30 carbon atoms or asubstituted or unsubstituted heteroaryl group having 5 to 30 carbonatoms, where in the case that o, p, q and r are independently greaterthan or equal to 2, Ar¹ may be the same or different, Ar² may be thesame or different, Ar³ may be the same or different, Ar⁴ may be the sameor different, and Ar¹, Ar², Ar³ and Ar⁴ may be the same from each other,or at least one thereof may be different.

In much further embodiments, the electron transport region may includeat least one compound selected from compounds represented in thefollowing Formula 6.

In other embodiments, display devices include a plurality of pixels. Oneof the pixels includes a first electrode, a hole transport regionprovided on the first electrode, an emission layer provided on the holetransport region, an electron transport region provided on the emissionlayer, and a second electrode provided on the electron transport region.The hole transport region includes a compound represented by thefollowing Formula 1.

In the above Formula 1, X, Y and Z are independently selected from thegroup consisting of hydrogen, deuterium, a substituted or unsubstitutedaromatic ring having 5 to 30 carbon atoms, a substituted orunsubstituted condensed aromatic ring having 5 to 30 carbon atoms, asubstituted or unsubstituted heteroaromatic ring having 5 to 30 carbonatoms, a substituted or unsubstituted condensed heteroaromatic ringhaving 5 to 30 carbon atoms, a substituted or unsubstitutedheteroaromatic ring having 5 to 30 carbon atoms and including N, S or O,and a substituted or unsubstituted condensed heteroaromatic ring having5 to 30 carbon atoms and including N, S or O.

In some embodiments, the hole transport region may include at least onecompound selected from compounds represented in the following Formula 2.

In other embodiments, the hole transport region may include a holeinjection layer provided on the first electrode and a hole transportlayer provided on the hole injection layer.

In still other embodiments, the emission layer may include a compoundrepresented by the following Formula 3.

In the above Formula 3, Ar¹¹ and Ar¹² are independently selected fromthe group consisting of hydrogen, deuterium, a substituted orunsubstituted aromatic ring having 5 to 30 carbon atoms, a substitutedor unsubstituted condensed aromatic ring having 5 to 30 carbon atoms, asubstituted or unsubstituted heteroaromatic ring having 5 to 30 carbonatoms, a substituted or unsubstituted condensed heteroaromatic ringhaving 5 to 30 carbon atoms, a substituted or unsubstitutedheteroaromatic ring having 5 to 30 carbon atoms and including N, S or O,and a substituted or unsubstituted condensed heteroaromatic ring having5 to 30 carbon atoms and including N, S or O, and m and n areindependently an integer of 0 to 3.

In even other embodiments, the emission layer may include at least onecompound selected from compounds represented in the following Formula 4.

In yet other embodiments, the electron transport region may include atleast one compound selected from compounds represented in the followingFormula 5.

In the above Formula 5, Ar¹, Ar², Ar³ and Ar⁴ are independently selectedfrom the group consisting of hydrogen, deuterium, a substituted orunsubstituted aromatic ring having 5 to 30 carbon atoms, a substitutedor unsubstituted condensed aromatic ring having 5 to 30 carbon atoms, asubstituted or unsubstituted heteroaromatic ring having 5 to 30 carbonatoms, a substituted or unsubstituted condensed heteroaromatic ringhaving 5 to 30 carbon atoms, a substituted or unsubstitutedheteroaromatic ring having 5 to 30 carbon atoms and including N, S or O,and a substituted or unsubstituted condensed heteroaromatic ring having5 to 30 carbon atoms and including N, S or O, and o, p, q and r areindependently an integer of 1 to 3.

In further embodiments, the electron transport region may include atleast one compound selected from compounds represented in the followingFormula 6.

In still further embodiments, the electron transport region may includean electron transport layer provided on the emission layer and anelectron injection layer provided on the electron transport layer.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will be apparent to those of skill in the art by describing indetail exemplary embodiments with reference to the attached drawings inwhich:

FIG. 1 illustrates a schematic cross-sectional view of an organic lightemitting device according to an embodiment;

FIG. 2 illustrates a schematic cross-sectional view of an organic lightemitting device according to an embodiment;

FIG. 3 illustrates a perspective view of a display device according toan embodiment;

FIG. 4 illustrates a circuit diagram of a pixel included in the displaydevice according to an embodiment;

FIG. 5 illustrates a plan view of a pixel included in the display deviceaccording to an embodiment; and

FIG. 6 illustrates a schematic cross-sectional view corresponding toline I-I′ in FIG. 5.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey exemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. Like reference numerals referto like elements throughout.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another element. For example, a first element discussedbelow could be termed a second element, and similarly, a second elementcould be termed a first element. As used herein, the singular forms areintended to include the plural forms as well, unless the context clearlyindicates otherwise.

It will be further understood that the terms “includes,” “comprises,”and/or “comprising,” when used in this specification, specify thepresence of stated features, steps, operations, and/or devices, but donot preclude the presence or addition of one or more other features,steps, operations, and/or devices thereof. It will also be understoodthat when a layer, a film, a region, a plate, etc. is referred to asbeing ‘on’ another part, it can be directly on the other part, orintervening layers may also be present. When a layer, a film, a region,a plate, etc. is referred to as being ‘under’ another part, it can bedirectly under the other part, or intervening layers may also bepresent.

Hereinafter, exemplary embodiments of the organic light emitting devicewill be described in detail.

FIG. 1 illustrates a schematic cross-sectional view of an organic lightemitting device according to an embodiment.

Referring to FIG. 1, an organic light emitting device OEL according toan embodiment may include a hole transport region HTR, an emission layerEML, and an electron transport region ETR.

FIG. 2 illustrates a schematic cross-sectional view of an organic lightemitting device according to an embodiment.

Referring to FIG. 2, an organic light emitting device OEL according toan embodiment may include a hole transport region HTR, an emission layerEML and an electron transport region ETR.

The hole transport region HTR may include a hole injection layer HIL anda hole transport layer HTL. The hole injection layer HIL may be providedon a first electrode EL1 (see FIG. 5). The hole transport layer HTL maybe provided on the hole injection layer HIL.

The electron transport region ETR may include an electron transportlayer ETL and an electron injection layer EIL. The electron transportlayer ETL may be provided on the emission layer EML. The electroninjection layer EIL may be provided on the electron transport layer ETL.

Referring to FIGS. 1 and 2, the first electrode EL1 has conductivity.The first electrode EL1 may be a pixel electrode or an anode.

The first electrode EL1 may be formed as a transparent electrode or areflective type electrode. When the first electrode EU is formed as thetransparent electrode, the first electrode EL1 may be formed using atransparent metal oxide, e.g., indium tin oxide (ITO), indium zinc oxide(IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. When thefirst electrode EL1 is formed as the reflective type electrode, thefirst electrode EL1 may include a reflection layer formed by using Ag,Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a compound thereof and atransparent conductive layer formed by using ITO, IZO, ZnO, ITZO, etc.

The organic light emitting device OEL may include an organic layer. Theorganic layer may be provided between the first electrode EL1 and thesecond electrode EL2. The organic layer may include the emission layerEML. The organic layer may further include the hole transport region HTRand the electron transport region ETR.

The hole transport region HTR may be provided on the first electrodeEL1. The hole transport region HTR may include, e.g., at least one of ahole injection layer, a hole transport layer, a buffer layer, and anelectron blocking layer.

The hole transport region HTR may have a single layer formed by using asingle material, a single layer formed by using a plurality of differentmaterials, or a multilayered structure including a plurality of layersformed by using a plurality of different materials.

For example, the hole transport region HTR may have the structure of asingle layer formed by using a plurality of different materials, or alaminated structure of, from the first electrode EL1, a hole injectionlayer HIL/hole transport layer HTL, hole injection layer HIL/holetransport layer HTL/buffer layer, hole injection layer HIL/buffer layer,hole transport layer HTL/buffer layer or hole injection layer HIL/holetransport layer HTL/electron blocking layer.

The hole transport region HTR may be formed by using various methodse.g., a vacuum deposition method, a spin coating method, a cast method,a Langmuir-Blodgett (LB) method, an inkjet printing method, a laserprinting method, a laser induced thermal imaging (LITI) method, etc.

The thickness of the hole transport region HTR may be from about 100 Åto about 10,000 Å, e.g., from about 100 Å to about 1,000 Å. When thehole transport region HTR includes both the hole injection layer HIL andthe hole transport layer HTL, the thickness of the hole injection layerHIL may be from about 100 Å to about 10,000 Å, e.g., from about 100 Å toabout 1,000 Å, and the thickness of the hole transport layer HTL may befrom about 50 Å to about 2,000 Å, e.g., from about 100 to about 1,500.When the thicknesses of the hole transport region HTR, the holeinjection layer HIL and the hole transport layer HTL satisfy theabove-described ranges, satisfactory hole transport properties may beobtained without substantial increase of a driving voltage.

The hole transport region HTR may include a compound represented by thefollowing Formula 1. In an implementation, the display device accordingto an embodiment may include an organic light emitting device includinga hole transport region including a compound represented by thefollowing Formula 1. Thus, a band gap between the energy band of thehole transport region and the energy band of the emission layer may bedecreased, and the injection of holes into the emission layer may becomeeasy. Thus, the display according to an embodiment may exhibit highefficiency and long life.

In the above Formula 1, X, Y, and Z may each independently be selectedfrom or include, e.g., hydrogen, deuterium, a substituted orunsubstituted aromatic ring or group having 5 to 30 carbon atoms (e.g.,a substituted or unsubstituted condensed aromatic group having 5 to 30carbon atoms), and a substituted or unsubstituted heteroaromatic grouphaving 5 to 30 carbon atoms (e.g., a substituted or unsubstitutedcondensed heteroaromatic group having 5 to 30 carbon atoms). In animplementation, X, Y, and Z may each independently be selected from orinclude, e.g., a substituted or unsubstituted heteroaromatic grouphaving 5 to 30 carbon atoms and including N, S or O, and a substitutedor unsubstituted condensed heteroaromatic group having 5 to 30 carbonatoms and including N, S or O.

In an implementation, X, Y, and Z may each independently be selectedfrom or include, e.g., hydrogen, deuterium, a substituted orunsubstituted aryl group having 5 to 30 carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 carbon atoms, asubstituted or unsubstituted aryloxy group having 5 to 30 carbon atoms,a substituted or unsubstituted arylamino group having 5 to 30 carbonatoms, a substituted or unsubstituted diarylamino group having 5 to 30carbon atoms, and a substituted or unsubstituted arylakyl group having 5to 30 carbon atoms.

In an implementation, X, Y, and Z may each independently be selectedfrom, e.g., a phenyl group, a naphthyl group, a biphenyl group, aterphenyl group, an anthracene group, a fluorenyl group, and acarbazolyl group.

In an implementation, the hole transport region HTR may include at leastone of the following compounds. For example, the compound represented byFormula 1 may be one of the following compounds.

When the hole transport region HTR includes the hole injection layerHIL, the hole transport region HTR may further include, e.g., aphthalocyanine compound such as copper phthalocyanine,N,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine(DNTPD), 4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine(m-MTDATA), 4,4′,4″-Tris(N,N-diphenylamino)triphenylamine (TDATA),4,4′,4″-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), polyaniline/camphorsulfonic acid (PANI/CSA), (polyaniline)/poly(4-styrenesulfonate)(PANI/PSS), etc.

When the hole transport region HTR includes the hole transport layerHTL, the hole transport region HTR may further include, e.g., acarbazole derivative such as N-phenylcarbazole, polyvinyl carbazole,etc., a fluorine-based derivative,N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine(TPD), a triphenylamine derivative such as4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), etc.,N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB), 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine (TAPC).

The hole transport region HTR may further include a charge generatingmaterial to help improve conductivity other than the above-describedmaterials. The charge generating material may be dispersed in the holetransport region HTR uniformly or non-uniformly. The charge generatingmaterial may be, e.g., a p-type dopant. The p-type dopant may be, e.g.,one of a quinone derivative, a metal oxide, and a cyano group-containingcompound. Examples of the p-dopant may include a quinone derivative suchas tetracyanoquinodimethane (TCNQ),2,3,5,6-tetrafluoro-tetracyanoquinodimethane (F4-TCNQ), etc., a metaloxide such as tungsten oxide, molybdenum oxide, etc.

As described above, the hole transport region HTR may further includeone of a buffer layer and an electron blocking layer other than the holeinjection layer HIL and the hole transport layer HTL. The buffer layermay compensate an optical resonance range according to the wavelength oflight emitted from the emission layer EML and increase light emissionefficiency. Materials included in the hole transport region HTR may beused as materials included in the buffer layer. The electron blockinglayer is a layer that helps prevent electron injection from the electrontransport region ETR.

The emission layer EML may be provided on the hole transport region HTR.The emission layer EML may have a single layer formed by using a singlematerial, a single layer formed by using a plurality of differentmaterials, or a multilayered structure including a plurality of layersformed by using a plurality of layers formed by using a plurality ofdifferent materials.

The emission layer EML may be formed by using various methods such as avacuum deposition method, a spin coating method, a cast method, a LBmethod, an inkjet printing method, a laser printing method, a LITImethod, etc.

The emission layer EML may be formed using suitable materials e.g.,materials emitting red, green, and blue light, and may include aphosphorescent material or a fluorescent material. In an implementation,the emission layer EML may include a host or a dopant.

The host may include a compound represented by the following Formula 3.The display according to an embodiment may include an organic lightemitting device including an emission layer including the compoundrepresented by the following Formula 3, and may decrease a band gapbetween the energy band of the hole transport region and the energy bandof the emission layer. And so, the hole injection into the emissionlayer may be easily performed. In addition, a band gap between theenergy band of the emission layer and the energy band of the electrontransport region may be decreased, and the electron injection into theemission layer may be easily performed. Therefore, the display accordingto an embodiment may exhibit high efficiency and long life.

In the above Formula 3, Ar¹¹ and Ar¹² may each independently be selectedfrom or include, e.g., hydrogen, deuterium, a substituted orunsubstituted aromatic group having 5 to 30 carbon atoms (e.g., asubstituted or unsubstituted condensed aromatic group having 5 to 30carbon atoms), and a substituted or unsubstituted heteroaromatic grouphaving 5 to 30 carbon atoms (e.g., a substituted or unsubstitutedcondensed heteroaromatic group having 5 to 30 carbon atoms). In animplementation, Ar¹¹ and Ar¹² may each independently be selected from orinclude, e.g., a substituted or unsubstituted heteroaromatic ring having5 to 30 carbon atoms and including N, S or O and a substituted orunsubstituted condensed heteroaromatic ring having 5 to 30 carbon atomsand including N, S or O. m and n may each independently be an integer of0 to 3.

In an implementation, Ar¹¹ may include, e.g., a substituted orunsubstituted arylene group having 7 to 30 carbon atoms or a substitutedor unsubstituted heteroarylene group having 7 to 30 carbon atoms. When mis 0, Ar¹¹ may be a single bond. In an implementation, Ar¹² may include,e.g., a substituted or unsubstituted aryl group having 5 to 30 carbonatoms or a substituted or unsubstituted heteroaryl group having 5 to 30carbon atoms. In the case that m or n is an integer greater than orequal to 2, Ar¹¹ may be the same or different, Ar¹² may be the same ordifferent, and Ar¹¹ and Ar¹² may be the same or different from eachother.

In an implementation, Ar¹¹ may include, e.g., a substituted orunsubstituted phenyl group or a substituted or unsubstituted naphthylgroup.

In an implementation, the host may include at least one of the followingcompounds. For example, the compound represented by Formula 3 may be oneof the following compounds.

The host may further include, e.g., tris(8-hydroxyquinolino)aluminum(Alq3), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP),poly(n-vinylcabazole) (PVK), 9,10-di(naphthalene-2-yl)anthracene (ADN),4,4′,4″-Tris(carbazol-9-yl)-triphenylamine (TCTA),1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBi),3-tert-butyl-9,10-di(naphth-2-yl)anthracene (TBADN), distyrylarylene(DSA), 4,4′-bis(9-carbazolyl)-2,2′-dimethyl-biphenyl (CDBP),2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), etc.

When the emission layer EML emits red light, the emission layer EML mayfurther include a phosphorescent material including, e.g.,tris(dibenzoylmethanato)phenanthoroline europium (PBD:Eu(DBM)3(Phen)) orperylene. When the emission layer EML emits red light, the dopantfurther included in the emission layer EML may be selected from a metalcomplex or an organometallic complex such asbis(1-phenylisoquinoline)acetylacetonate iridium (PIQIr(acac)),bis(1-phenylquinoline)acetylacetonate iridium (PQIr(acac),tris(1-phenylquinoline)iridium (PQIr), and octaethylporphyrin platinum(PtOEP).

When the emission layer EML emits green light, the emission layer EMLmay further include a phosphorescent material including, e.g., Alq3.When the emission layer EML emits green light, the dopant furtherincluded in the emission layer EML may be selected from a metal complexor an organometallic complex such as fac-tris(2-phenylpyridine)iridium(Ir(ppy)3).

When the emission layer EML emits blue light, the emission layer EML mayfurther include a phosphorescent material including at least oneselected from, e.g., spiro-DPVBi (DPVBi), spiro-6P, distyryl-benzene(DSB), distyryl-arylene (DSA), polyfluorene (PFO)-based polymer andpoly(p-phenylene vinylene) (PPV)-based polymer. When the emission layerEML emits blue light, the dopant further included in the emission layerEML may be selected from a metal complex or an organometallic complexsuch as (4,6-F2ppy)2Irpic.

As described above, the organic layer may further include the electrontransport region ETR. The electron transport region ETR may be providedon the emission layer EML.

The electron transport region ETR may include, e.g., at least one of ahole blocking layer, an electron transport layer ETL, and an electroninjection layer EIL.

For example, the electron transport region ETR may have the structure ofa laminated structure of, from the emission layer EML, an electrontransport layer ETL/electron injection layer EIL or hole blockinglayer/electron transport layer ETL/electron injection layer EIL, or asingle layer structure of the mixture of at least two of the abovelayers.

The electron transport region ETR may be formed by using various methodse.g., a vacuum deposition method, a spin coating method, a cast method,a LB method, an inkjet printing method, a laser printing method, a LITImethod, etc.

The electron transport region ETR may include, e.g., at least onecompound of the following Formula 5. The display device according to anembodiment may include, e.g., an organic light emitting device includinga compound of the following Formula 5. Thus, a band gap between theenergy band of the emission layer and the energy band of the electrontransport layer may be decreased, and the injection of electrons intothe emission layer may become easy. Thus, the display according to anembodiment may exhibit high efficiency and long life.

In the compounds of Formula 5, Ar¹, Ar², Ar³, and Ar⁴ may eachindependently be selected from or include, e.g., hydrogen, deuterium, asubstituted or unsubstituted aromatic group having 5 to 30 carbon atoms(e.g., a substituted or unsubstituted condensed aromatic group having 5to 30 carbon atoms), and a substituted or unsubstituted heteroaromaticgroup having 5 to 30 carbon atoms (e.g., a substituted or unsubstitutedcondensed heteroaromatic group having 5 to 30 carbon atoms). In animplementation, Ar¹, Ar², Ar³, and Ar⁴ may each independently beselected from or include, e.g., a substituted or unsubstitutedheteroaromatic ring having 5 to 30 carbon atoms and including N, S or Oand a substituted or unsubstituted condensed heteroaromatic ring having5 to 30 carbon atoms and including N, S or O. o, p, q and r may eachindependently be, e.g., an integer of 1 to 3.

In an implementation, Ar¹, Ar², Ar³, and Ar⁴ may each independently beselected from or include, e.g., a substituted or unsubstituted arylgroup having 5 to 30 carbon atoms or a substituted or unsubstitutedheteroaryl group having 5 to 30 carbon atoms. In the case that o, p, q,and/or r are each independently greater than or equal to 2, Ar¹ may bethe same or different, Ar² may be the same or different, Ar³ may be thesame or different, Ar⁴ may be the same or different, and Ar1, Ar2, Ar³and Ar⁴ may be the same, or at least one thereof may be different.

The electron transport region ETR may include, e.g., at least one of thefollowing compounds. For example, the compound of Formula 5 may be oneof the following compounds.

When the electron transport region ETR includes the electron transportlayer ETL, the electron transport region ETR may further include, e.g.,Alq3, TPBi, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP),4,7-diphenyl-1,10-phenanthroline (Bphen),3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ),4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ),(2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD),bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-biphenyl-4-olato)aluminum(BAlq), berylliumbis(benzoquinolin-10-olate) (Bebq2), ADN, and a mixturethereof.

The thickness of the electron transport layer ETR may be from about 100Å to about 1,000 Å, e.g., from about 150 Å to about 500 Å. When thethickness of the electron transport layer ETL satisfies the abovedescribed range, satisfactory electron transport properties may beobtained without inducing substantial increase of a driving voltage.

When the electron transport region ETR includes the electron injectionlayer EIL, the electron transport region ETR may further include, e.g.,LiF, lithium quinolate (LiQ), Li₂O, BaO, NaCl, CsF, a lanthanide such asYb, or a metal halide such as RbCl and RbI. The electron injection layerEIL also may be formed using a mixed material of the hole transportmaterial and an insulating organo metal salt. The organo metal salt maybe a material having an energy band gap of greater than or equal toabout 4 eV. In an implementation, the organo metal salt may include,e.g., a metal acetate, a metal benzoate, a metal acetoacetate, a metalacetylacetonate, or a metal stearate.

The thickness of the electron injection layer EIL may be from about 1 Åto about 100 Å, e.g., from about 3 Å to about 90 Å. When the thicknessof the electron injection layer EIL satisfies the above described range,satisfactory electron injection properties may be obtained withoutinducing the substantial increase of a driving voltage.

The electron transport region ETR may include a hole blocking layer, asdescribed above. The hole blocking layer may include at least one of,e.g., BCP and Bphen. The thickness of the hole blocking layer may befrom about 20 Å to about 1,000 Å, e.g., from about 30 Å to about 300 Å.When the thickness of the hole blocking layer satisfies the abovedescribed range, satisfactory electron injection properties may beobtained without inducing the substantial increase of a driving voltage.

The second electrode EL2 may be provided on the electron transportregion ETR. The second electrode EL2 may be a common electrode or acathode. The second electrode EL2 may be a transmissive electrode,transflective electrode, or reflective electrode.

When the second electrode EL2 is the transmissive electrode, the secondelectrode EL2 may include Li, Ca, LiF/Ca, LiF/Al, Al, Mg, Ag, a compoundthereof or a mixture thereof (e.g., a mixture of Ag and Mg). The secondelectrode EL2 may include an auxiliary electrode. The auxiliaryelectrode may include a layer formed by depositing the above-describedmaterial toward an emission layer, a transparent metal oxide on thelayer, for example, ITO, IZO, ZnO, ITZO, etc.

When the second electrode EL2 is the transflective electrode or thereflective electrode, the second electrode EL2 may include Ag, Mg, Al,Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, a compound thereofor a mixture thereof (for example, a mixture of Ag and Mg). The secondelectrode EL2 may be a reflective layer or a transflective layer formedusing the above material and a multilayered structure including atransparent conductive layer formed using ITO, IZO, ZnO, ITZO, etc.

When the organic light emitting device OEL is a front luminescent type,the first electrode EU may be the reflective type electrode, and thesecond electrode EL2 may be the transmissive electrode or thetransflective electrode. When the organic light emitting device OEL is abackside luminescent type, the first electrode EL1 may be thetransmissive electrode or the transflective electrode, and the secondelectrode EL2 is the reflective electrode.

In the organic light emitting device OEL according to an embodiment,according to the application of a voltage to the first electrode EL1 andthe second electrode EL2, respectively, holes injected from the firstelectrode EL1 may move via the hole transport region HTR to the emissionlayer EML, and electrons injected from the second electrode EL2 may movevia the electron transport region ETR to the emission layer EML. Theelectrons and the holes may be recombined in the emission layer EML togenerate excitons, and light is emitted during the transition of theexcitons from an excited state to a ground state.

Generally, the moving velocity of electrons may be smaller than that ofholes in an organic light emitting device, and a band gad between theenergy band of a hole transport region and the energy band of anemission layer and a band gap between the energy band of the emissionlayer and the energy band of an electron transport region may begenerated. Thus, the probability of the meeting of the electrons and theholes in the emission layer may be low, and the injection of the holesand electrons into the emission layer is not easy, thereby deterioratingemission efficiency.

The display according to an embodiment may include a hole transportregion containing a compound represented by the above Formula 1, anemission layer containing a compound represented by the above Formula 3,and an organic light emitting device containing a compound representedby the above Formula 5. Thus, the band gap between the energy band ofthe hole transport region and the energy band of the emission layer maybe decreased, and the hole injection to the emission layer may becomeeasy. In addition, the band gap between the energy band of the emissionlayer and the energy band of the electron transport region may bedecreased, and the electron injection into the emission layer may becomeeasy. Accordingly, the display according to an embodiment may realizehigh efficiency and long life.

Hereinafter, the display according to an embodiment will be explained.The explanation will be concentrated on different points from theorganic light emitting device OEL according to an embodiment describedabove, and unexplained parts will follow the explanation on the organiclight emitting device according to an embodiment described above.

FIG. 3 illustrates a perspective view of display device 10 according toan embodiment.

Referring to FIG. 3, a display 10 according to an embodiment mayinclude, e.g., a display area DA and a non-display area NDA.

The display area DA may display an image. When seen from the directionof the thickness of the display 10 (e.g., in DR3), the display area DAmay have, e.g., approximately a rectangle shape.

The display area DA may include a plurality of pixel areas PA. The pixelareas PA may be disposed in a matrix shape. The pixel areas PA may bedefined by a pixel defining layer (PDL in FIG. 6). Each pixel area PAmay include a plurality of pixels (PX in FIG. 4).

A non-display area NDA does not display an image. When seen from thedirection of the thickness of the display 100 (e.g., in DR3), thenon-display area NDA may be, e.g., surrounded by the display area DA.The non-display area NDA may be adjacent to the display area DA in afirst direction (e.g., in DR1) and a second direction (e.g., in DR2)which is perpendicular to the first direction (e.g., DR1).

FIG. 4 illustrates a circuit diagram of a pixel included in the displaydevice 10 according to an embodiment.

FIG. 5 illustrates a plan view of a pixel included in the display device10 according to an embodiment.

FIG. 6 illustrates a schematic cross-sectional view corresponding toline I-I′ in FIG. 5.

Referring to FIGS. 4 to 6, each pixel PX may include a wire partincluding a gate line GL, a data line DL and a driving voltage line DVL,thin film transistors TFT1 and TFT2 connected to the wire part, anorganic light emitting device OEL connected to the thin film transistorsTFT1 and TFT2, and a capacitor Cst.

Each pixel may emit light having a specific color, e.g., one of redlight, green light and blue light. In an implementation, the kind ofcolor light may include, e.g., cyan light, magenta light, yellow light,etc.

The gate line GL may be extended in the first direction DR1. The dataline DL may be extended in the second direction DR2 crossing the gateline GL. The driving voltage line DVL may be extended in substantiallythe same direction as the data line DL, e.g., the second direction DR2.The gate line GL transmits scanning signal to the thin film transistorsTFT1 and TFT2, and the data line DL transmits data signal to the thinfilm transistors TFT1 and TFT2, and the driving voltage line DVLprovides a driving voltage to the thin film transistors.

The thin film transistors TFT1 and TFT2 may include a driving thin filmtransistor TFT2 for controlling the organic light emitting device OELand a switching thin film transistor TFT1 for switching the driving thinfilm transistor TFT2. In an implementation, each pixel PX may includetwo thin film transistors TFT1 and TFT2. Each pixel PX may include onethin film transistor and one capacitor, or each pixel PX may include atleast three thin film transistors and at least two capacitors.

The switching thin film transistor TFT1 may include a first gateelectrode GE1, a first source electrode SE1 and a first drain electrodeDE1. The first gate electrode GE1 may be connected to the gate line GL,and the first source electrode SE1 may be connected to the data line DL.The first drain electrode DE1 may be connected to a first commonelectrode CE1 via a fifth contact hole CH5. The switching thin filmtransistor TFT1 transmits data signal applied to the data line DL to thedriving thin film transistor TFT2 according to scanning signal appliedto the gate line GL.

The driving thin film transistor TFT2 may include a second gateelectrode GE2, a second source electrode SE2, and a second drainelectrode DE2. The second gate electrode GE2 may be connected to thefirst common electrode CE1. The second source electrode SE2 may beconnected to the driving voltage line DVL. The second drain electrodeDE2 may be connected to the first electrode EL1 by a third contact holeCH3.

The organic light emitting device OEL may be between an embossing firstelectrode B_EL1 and a second electrode EL2. The embossing firstelectrode B_EL1 may be connected to a second drain electrode DE2 of thedriving thin film transistor TFT2. To the second electrode EL2, a commonvoltage may be applied, and the emission layer EML emits blue lightaccording to the output signal of the driving thin film transistor TFT2,thereby displaying images. The organic light emitting device OEL, theembossing first electrode B_EL1 and the second electrode EL2 will beparticularly described below.

The capacitor Cst may be connected between the second gate electrode GE2and the second source electrode SE2 of the driving thin film transistorTFT2 and may charge and maintain data signal inputted to the second gateelectrode GE2 of the driving thin film transistor TFT2. The capacitorCst may include the first common electrode CE1 connected to the firstdrain electrode DE1 via a sixth contact hole CH6 and a second commonelectrode CE2 connected to the driving voltage line DVL.

Referring to FIGS. 5 and 6, the display 10 according to an embodimentmay include a substrate SUB on which a thin film transistor and theorganic light emitting device OEL are stacked. Suitable substrates maybe used as the substrate SUB, and may be formed using an insulatingmaterial, e.g., glass, plastics, quartz, etc. As an organic polymerforming the substrate SUB, polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polyimide, polyethersulfone, etc. may beused. The substrate SUB may be selected in consideration of mechanicalstrength, thermal stability, transparency, surface smoothness, easinessof handling, water-proof properties, etc.

On the substrate SUB, a substrate buffer layer (not shown) may beprovided. The substrate buffer layer (not shown) prevents the diffusionof impurities into the switching thin film transistor TFT1 and thedriving thin film transistor TFT2. The substrate buffer layer (notshown) may be formed using silicon nitride (SiNx), silicon oxide (SiOx),silicon oxynitride (SiOxNy), etc., and may be omitted according to thematerial of the substrate SUB and process conditions.

On the substrate SUB, a first semiconductor layer SM1 and a secondsemiconductor layer SM2 are provided. The first semiconductor layer SM1and the second semiconductor layer SM2 may be formed using asemiconductor material and function as an active layer of a switchingthin film transistor TFT1 and a driving thin film transistor TFT2,respectively. Each of the first semiconductor layer SM1 and the secondsemiconductor layer SM2 includes a source area SA, a drain area DA and achannel area CA provided between the source area SA and the drain areaDA. Each of the first semiconductor layer SM1 and the secondsemiconductor layer SM2 may be formed by selecting an inorganicsemiconductor or an organic semiconductor, respectively. The source areaSA and the drain area DA may be doped with n-type impurities or p-typeimpurities.

On the first semiconductor layer SM1 and the second semiconductor layerSM2, a gate insulating layer GI may be provided. The gate insulatinglayer GI covers the first semiconductor layer SM1 and the secondsemiconductor layer SM2. The gate insulating layer GI may be formedusing an organic insulating material or an inorganic insulatingmaterial.

On the gate insulating layer GI, a first gate electrode GE1 and a secondgate electrode GE2 are provided. Each of the first gate electrode GE1and the second gate electrode GE2 are formed to cover a correspondingarea in the channel area CA of the first semiconductor layer SM1 and thesecond semiconductor layer SM2.

On the first gate electrode GE1 and the second gate electrode GE2, aninsulating interlayer IL may be provided. The insulating interlayer ILcovers the first gate electrode GE1 and the second gate electrode GE2.The insulating interlayer IL may be formed using an organic insulatingmaterial or an inorganic insulating material.

On the insulating interlayer IL, a first source electrode SE1, a firstdrain electrode DE1, a second source electrode SE2 and a second drainelectrode DE2 may be provided. The second drain electrode DE2 makes acontact with the drain area DA of the second semiconductor layer SM2 viaa first contact hole CH1 formed in a gate insulating layer GI and theinsulating interlayer IL, and the second source electrode SE2 makes acontact with the source area SA of a second semiconductor layer SM2 by asecond contact hole CH2 formed in the gate insulating layer GI and theinsulating interlayer IL. The first source electrode SE1 makes a contactwith the source area (not shown) of the first semiconductor layer SM1via a fourth contact hole CH4 formed in the gate insulating layer GI andthe insulating interlayer IL, and the first drain electrode DE1 makes acontact with the drain area (not shown) of the first semiconductor layerSM1 by a fifth contact hole CH5 formed in the gate insulating layer GIand the insulating interlayer IL.

On the first source electrode SE1, the first drain electrode DE1, thesecond source electrode SE2 and the second drain electrode DE2, apassivation layer PL may be provided. The passivation layer PL may playthe role of the switching thin film transistor TFT1 and the driving thinfilm transistor TFT2, or the role of a planarization layer forplanarizing the top surface thereof.

On the passivation layer PL, a first electrode EU may be provided. Thefirst electrode EL1 may be, e.g., an anode. The first electrode EL1 maybe connected to the second drain electrode DE2 of the driving thin filmtransistor TR2 via the third contact hole CH3 formed in the passivationlayer PL.

On the passivation layer PL, a pixel defining layer PDL for partitioningpixel areas (PA in FIG. 3) corresponding to each of the pixels PX may beprovided. The pixel defining layer PDL exposes the top surface of thefirst electrode EL1 and may be extruded from the substrate SUB along thecircumference of each of the pixels PX. The pixel defining layer PDL mayinclude, e.g., a metal fluoride ion compound. For example, the pixeldefining layer PDL may be formed using LiF, BaF₂, or CsF. When the metalfluoride ion compound has a certain thickness, insulating properties maybe obtained. The thickness of the pixel defining layer PDL may be, e.g.,from about 10 nm to about 100 nm.

To each pixel area (PA in FIG. 3) surrounded by the pixel defining layerPDL, an organic light emitting device OEL is provided. The organic lightemitting device OEL includes a hole transport region HTR, an emissionlayer EML, and an electron transport region ETR.

The hole transport region HTR may include a hole injection layer HIL anda hole transport layer HTL. The hole injection layer HIL may be providedon a first electrode EL1. The hole transport layer HTL may be providedon the hole injection layer HIL.

The electron transport region ETR may include an electron transportlayer ETL and an electron injection layer EIL. The electron transportlayer ETL may be provided on the emission layer EML. The electroninjection layer EIL may be provided on the electron transport layer ETL.

The hole transport region HTR may include a compound represented by thefollowing Formula 1. The display according to an embodiment may includean organic light emitting device including a hole transport regionincluding the compound represented by the following Formula 1, therebydecreasing a band gap between the energy band of the hole transportregion and the energy band of the emission layer and facilitating holeinjection into the emission layer. Thus, the display according to anembodiment may realize high efficiency and long life.

In the above Formula 1, X, Y, and Z may each independently be selectedfrom or include, e.g., hydrogen, deuterium, a substituted orunsubstituted aromatic group having 5 to 30 carbon atoms (e.g., asubstituted or unsubstituted condensed aromatic group having 5 to 30carbon atoms), and a substituted or unsubstituted heteroaromatic grouphaving 5 to 30 carbon atoms (e.g., a substituted or unsubstitutedcondensed heteroaromatic group having 5 to 30 carbon atoms). In animplementation, X, Y, and Z may each independently be selected from orinclude, e.g., a substituted or unsubstituted heteroaromatic grouphaving 5 to 30 carbon atoms and including N, S or O, and a substitutedor unsubstituted condensed heteroaromatic group having 5 to 30 carbonatoms and including N, S or O.

In an implementation, X, Y, and Z may each independently be selectedfrom or include, e.g., hydrogen, deuterium, a substituted orunsubstituted aryl group having 5 to 30 carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 carbon atoms, asubstituted or unsubstituted aryloxy group having 5 to 30 carbon atoms,a substituted or unsubstituted arylamino group having 5 to 30 carbonatoms, a substituted or unsubstituted diarylamino group having 5 to 30carbon atoms, and a substituted or unsubstituted arylakyl group having 5to 30 carbon atoms.

In an implementation, X, Y, and Z may each independently be selectedfrom, e.g., a phenyl group, a naphthyl group, a biphenyl group, aterphenyl group, an anthracene group, a fluorenyl group, and acarbazolyl group.

The hole transport region HTR may include at least one of the followingcompounds.

The emission layer EML may be provided on the hole transport region HTR.The emission layer EML may be formed using suitable materials, e.g.,materials emitting red, green, and blue light and may include aphosphorescent material or a fluorescent material. In addition, theemission layer EML may include a host or a dopant.

The host may include a compound represented by the following Formula 3.The display according to an embodiment may include an organic lightemitting device including an emission layer including the compoundrepresented by the following Formula 3, and may decrease a band gapbetween the energy band of the hole transport region and the energy bandof the emission layer. Thus, the hole injection into the emission layermay be easily performed. In addition, a band gap between the energy bandof the emission layer and the energy band of the electron transportregion may be decreased, and the electron injection into the emissionlayer may be easily performed. Therefore, the display according to anembodiment may exhibit high efficiency and long life.

In the above Formula 3, Ar¹¹ and Ar¹² may each independently be selectedfrom or include, e.g., hydrogen, deuterium, a substituted orunsubstituted aromatic group having 5 to 30 carbon atoms, (e.g., asubstituted or unsubstituted condensed aromatic group having 5 to 30carbon atoms), and a substituted or unsubstituted heteroaromatic grouphaving 5 to 30 carbon atoms (e.g., a substituted or unsubstitutedcondensed heteroaromatic group having 5 to 30 carbon atoms). In animplementation, Ar¹¹ and Ar¹² may each independently be selected from orinclude, e.g., a substituted or unsubstituted heteroaromatic grouphaving 5 to 30 carbon atoms and including N, S or O, and a substitutedor unsubstituted condensed heteroaromatic group having 5 to 30 carbonatoms and including N, S or O. m and n may each independently be aninteger of 0 to 3.

In an implementation, Ar¹¹ may include, e.g., a substituted orunsubstituted arylene group having 7 to 30 carbon atoms or a substitutedor unsubstituted heteroarylene group having 7 to 30 carbon atoms. In thecase that m is 0, Ar¹¹ may be a single bond. In an implementation, Ar¹²may include, e.g., a substituted or unsubstituted aryl group having 5 to30 carbon atoms or a substituted or unsubstituted heteroaryl grouphaving 5 to 30 carbon atoms. In the case that m or n is an integergreater than or equal to 2, Ar¹¹ may be the same or different, Ar¹² maybe the same or different, and Ar¹¹ and Ar¹² may be the same or differentfrom each other.

In an implementation, Ar¹¹ may be, e.g., a substituted or unsubstitutedphenyl group or a substituted or unsubstituted naphthyl group.

In an implementation, the host may include at least one of the followingcompounds.

The electron transport region ETR may be provided on the emission layerEML. The electron transport region ETR may include at least one compoundof the following Formula 5. The display device according to anembodiment may include an organic light emitting device including acompound of the following Formula 5. Thus, a band gap between the energyband of the emission layer and the energy band of the electron transportlayer may be decreased, and the injection of electrons into the emissionlayer may become easy. Thus, the display according to an embodiment mayexhibit high efficiency and long life.

In the above compounds, Ar¹, Ar², Ar³, and Ar⁴ may each independently beselected from or include, e.g., hydrogen, deuterium, a substituted orunsubstituted aromatic group having 5 to 30 carbon atoms (e.g., asubstituted or unsubstituted condensed aromatic group having 5 to 30carbon atoms), and a substituted or unsubstituted heteroaromatic grouphaving 5 to 30 carbon atoms (e.g., a substituted or unsubstitutedcondensed heteroaromatic group having 5 to 30 carbon atoms). In animplementation, Ar¹, Ar², Ar³, and Ar⁴ may each independently beselected from or include, e.g., a substituted or unsubstitutedheteroaromatic group having 5 to 30 carbon atoms and including N, S or Oand a substituted or unsubstituted condensed heteroaromatic group having5 to 30 carbon atoms and including N, S or O. o, p, q, and r may eachindependently be an integer of 1 to 3.

In an implementation, Ar¹, Ar², Ar³, and Ar⁴ may each independently beselected from or include, e.g., a substituted or unsubstituted arylgroup having 5 to 30 carbon atoms or a substituted or unsubstitutedheteroaryl group having 5 to 30 carbon atoms. In the case that o, p, q,and/or r are independently greater than or equal to 2, Ar¹ may be thesame or different, Ar² may be the same or different, Ar³ may be the sameor different, Ar⁴ may be the same or different, and Ar1, Ar2, Ar³ andAr⁴ may be the same from each other, or at least one thereof may bedifferent.

The electron transport region ETR may include at least one of thefollowing compounds.

On the second electrode EL2, a sealing layer SL covering the secondelectrode EL2 may be provided. The sealing layer may include at leastone of an organic layer and an inorganic layer. The sealing layer SLpassivates the organic light emitting device OEL.

Generally, the moving velocity of electrons may be smaller than that ofholes in an organic light emitting device, and a band gad between theenergy band of a hole transport region and the energy band of anemission layer and a band gap between the energy band of the emissionlayer and the energy band of an electron transport region may begenerated. Thus, the probability of the meeting of the electrons and theholes in the emission layer may be low, and the injection of the holesand electrons into the emission layer is not easy, thereby deterioratingemission efficiency.

The display according to an embodiment may include a hole transportregion containing a compound represented by the above Formula 1, anemission layer containing a compound represented by the above Formula 3,and an organic light emitting device containing a compound of the aboveFormula 5 (e.g., in the electron transport region). Thus, the band gapbetween the energy band of the hole transport region and the energy bandof the emission layer may be decreased, and the hole injection into theemission layer may become easy. In addition, the band gap between theenergy band of the emission layer and the energy band of the electrontransport region may be decreased, and the electron injection into theemission layer may become easy. Accordingly, the display according to anembodiment may realize high efficiency and long life.

The following Examples and Comparative Examples are provided in order tohighlight characteristics of one or more embodiments, but it will beunderstood that the Examples and Comparative Examples are not to beconstrued as limiting the scope of the embodiments, nor are theComparative Examples to be construed as being outside the scope of theembodiments. Further, it will be understood that the embodiments are notlimited to the particular details described in the Examples andComparative Examples.

EXAMPLES Example 1

On a glass substrate, an anode was formed using ITO to a thickness ofabout 120 nm. After performing ultrasonic washing and pre-treatment(UV-O₃ treatment, heat treatment), the following compound HT1 wasdeposited on the anode to a thickness of about 50 nm to from a holeinjection layer. On the hole injection layer, the following compound HT2was deposited to a thickness of about 45 nm to form a hole transportlayer. On the hole transport layer, the following compound H1 as a hostmaterial and 5% of the following compound D1 as a dopant were depositedat the same time to a thickness of about 50 nm to form an emissionlayer. On the emission layer, the following compound E1 as an electrontransporting material was deposited to a thickness of about 25 nm toform an electron transport region. On the electron transport region,lithium fluoride was deposited to a thickness of about 0.5 nm, and onthe lithium fluoride, aluminum was deposited to a thickness of about 150nm to form a cathode.

Examples 2 to 6

Organic light emitting devices were manufactured by performing the sameprocedure described in Example 1 except for forming the hole transportlayer using compounds described in the following Table 1.

TABLE 1 Compounds of hole transport layer Example 2 HT3 Example 3 HT4Example 4 HT5 Example 5 HT6 Example 6 HT7

Experimental Results

Current efficiency and life of the organic light emitting devices ofExamples 1 to 6 were measured, and the results are illustrated in thefollowing Table 2. The current efficiency of the organic light emittingdevice was measured in the conditions of the current density of 10mA/cm², and the life was obtained by measuring a time period whenluminance was decreased to 80% from an initial luminance value in theconditions of the current density of 50 mA/cm².

TABLE 2 Efficiency (cd/A) Life (hr) Example 1 5.2 100 Example 2 5.1 150Example 3 5.0 130 Example 4 5.2 135 Example 5 5.1 147 Example 6 5.2 131

Referring to the above Table 2, it may be seen that each organic lightemitting device of Examples 1 to 6 has high efficiency and long life.

The embodiments may provide an organic light emitting device having highefficiency and long life.

The embodiments may provide a display device including the organic lightemitting device having high efficiency and long life.

In the organic light emitting device according to an embodiment,efficiency may be increased, and life may be extended.

In the display device according to an embodiment, efficiency may beincreased, and life may be extended.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. An organic light emitting device, comprising: a first electrode; a hole transport region on the first electrode; an emission layer on the hole transport region; an electron transport region on the emission layer; and a second electrode on the electron transport region, wherein the hole transport region includes a compound represented by the following Formula 1:

wherein, in Formula 1, X, Y, and Z are each independently selected from hydrogen, deuterium, a substituted or unsubstituted aromatic group having 5 to 30 carbon atoms, and a substituted or unsubstituted heteroaromatic group having 5 to 30 carbon atoms.
 2. The organic light emitting device as claimed in claim 1, wherein X, Y, and Z are each independently selected from hydrogen, deuterium, a substituted or unsubstituted aryl group having 5 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 5 to 30 carbon atoms, a substituted or unsubstituted diarylamino group having 5 to 30 carbon atoms, and a substituted or unsubstituted arylakyl group having 5 to 30 carbon atoms.
 3. The organic light emitting device as claimed in claim 1, wherein X, Y, and Z are each independently selected from a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, an anthracene group, a fluorenyl group, and a carbazolyl group.
 4. The organic light emitting device as claimed in claim 1, wherein the hole transport region includes at least one of the following compounds:


5. The organic light emitting device as claimed in claim 1, wherein the emission layer includes a compound represented by the following Formula 3:

wherein, in Formula 3, Ar¹¹ and Ar¹² are each independently selected from hydrogen, deuterium, a substituted or unsubstituted aromatic group having 5 to 30 carbon atoms, and a substituted or unsubstituted heteroaromatic group having 5 to 30 carbon atoms, and m and n are each independently an integer of 0 to
 3. 6. The organic light emitting device as claimed in claim 5, wherein: Ar¹¹ is a substituted or unsubstituted arylene group having 7 to 30 carbon atoms or a substituted or unsubstituted heteroarylene group having 7 to 30 carbon atoms, when m is 0, Ar¹¹ is a single bond, Ar¹² is a substituted or unsubstituted aryl group having 5 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms, and when m or n is an integer greater than or equal to 2, Ar¹¹ is the same or different, Ar¹² is the same or different, and Ar¹¹ and Ar¹² are the same or different from each other.
 7. The organic light emitting device as claimed in claim 5, wherein Ar¹¹ is a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group.
 8. The organic light emitting device as claimed in claim 5, wherein the emission layer includes one of the following compounds:


9. The organic light emitting device as claimed in claim 1, wherein the electron transport region includes a compound of the following Formula 5:

wherein, in the compounds of Formula 5, Ar¹, Ar², Ar³, and Ar⁴ are each independently selected from hydrogen, deuterium, a substituted or unsubstituted aromatic group having 5 to 30 carbon atoms, and a substituted or unsubstituted heteroaromatic group having 5 to 30 carbon atoms, and o, p, q, and r are each independently an integer of 1 to
 3. 10. The organic light emitting device as claimed in claim 9, wherein: Ar¹, Ar², Ar³ and Ar⁴ are each independently a substituted or unsubstituted aryl group having 5 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms, and when o, p, q, or r are greater than or equal to 2, each Ar¹ is the same or different, each Ar² is the same or different, each Ar³ is the same or different, or each Ar⁴ is the same or different.
 11. The organic light emitting device as claimed in claim 9, wherein the electron transport region includes one of the following compounds:


12. A display device, comprising a plurality of pixels, wherein one of the pixels includes: a first electrode; a hole transport region on the first electrode; an emission layer on the hole transport region; an electron transport region on the emission layer; and a second electrode on the electron transport region, wherein the hole transport region includes a compound represented by the following Formula 1:

wherein, in Formula 1, X, Y, and Z are each independently selected from hydrogen, deuterium, a substituted or unsubstituted aromatic group having 5 to 30 carbon atoms, and a substituted or unsubstituted heteroaromatic group having 5 to 30 carbon atoms.
 13. The display device as claimed in claim 12, wherein the hole transport region includes at least one of the following compounds:


14. The display device as claimed in claim 12, wherein the hole transport region includes a hole injection layer on the first electrode; and a hole transport layer on the hole injection layer.
 15. The display device as claimed in claim 12, wherein the emission layer includes a compound represented by the following Formula 3:

wherein, in Formula 3, Ar¹¹ and Ar¹² are each independently selected from hydrogen, deuterium, a substituted or unsubstituted aromatic group having 5 to 30 carbon atoms, and a substituted or unsubstituted heteroaromatic group having 5 to 30 carbon atoms, and m and n are each independently an integer of 0 to
 3. 16. The display device as claimed in claim 15, wherein the emission layer includes one of the following compounds:


17. The display device as claimed in claim 12, wherein the electron transport region includes a compound of the following Formula 5:

wherein, in the compounds of Formula 5, Ar¹, Ar², Ar³, and Ar⁴ are each independently selected from hydrogen, deuterium, a substituted or unsubstituted aromatic group having 5 to 30 carbon atoms, a substituted or unsubstituted condensed aromatic group having 5 to 30 carbon atoms, a substituted or unsubstituted heteroaromatic group having 5 to 30 carbon atoms, and a substituted or unsubstituted condensed heteroaromatic group having 5 to 30 carbon atoms, and o, p, q, and r are each independently an integer of 1 to
 3. 18. The display device as claimed in claim 12, wherein the electron transport region includes one of the following compounds:


19. The display device as claimed in claim 12, wherein the electron transport region includes an electron transport layer on the emission layer; and an electron injection layer on the electron transport layer. 